It had various meaning in early Middle English, including "man of the common people," "a country man," "husbandman," "free peasant;" by 1300, it meant "bondman, villain," also "fellow of low birth or rude manners." For words for "common man" that acquire an insulting flavor over time, compare boor, villain. In this case, however, the same word also has come to mean "king" in many languages (e.g. Lithuanian karalius, Czech kral, Polish krol) via Charlemagne.